The introduction of swine (Sus scrofa) has adversely affected the environment of many natural habitats throughout the world. Basin marshes are dwindling ecosystems in Florida that are especially vulnerable to damage by feral swine. In January 2003, the estimated amount of swine damage to the exposed portion of the last remnant of a basin marsh system in Savannas Preserve State Park (SPSP) was 19% (an area of 5 ha). Economic valuations for the swine damage were based on the monetary amounts that wetland regulators have allowed permit applicants to spend in mitigation attempts to replace lost wetland resources. In 2003, the area of natural habitat damaged by swine had a total value of US$ 1 238 760–4 036 290. The SPSP implemented a contract for swine control throughout 2003 in all areas of the Park. The damage to the basin marsh was re-estimated in January 2004, after swine removal. The damage sampling transects remained the same as the 2003 survey, but damage was significantly reduced, with 31% of sampling transects showing damage in January 2004 versus 92% in January 2003. Similarly, the total area of swine damage had decreased to 0.95 ha, and the value of the lost habitat had been reduced to US$ 235 355–766 865, an economic benefit of US$ 1 003 355–3 269 265. The benefit-cost ratio (BCR) relating the economic value of the damage reduction against the swine control costs (not all swine control in the park was carried out in the vicinity of the basin marsh) was conservatively estimated at 134–436. When estimating costs for swine control in the vicinity of the marsh based on the proportional number of swine removed there as compared to the Park as a whole, the BCR increased to 480–1562. Benefits of swine removal are very high relative to the costs of control.

Feral swine (Sus scrofa) adversely affect the environment in many of the places where they have been introduced. Such is the case in Florida, but quantification and economic evaluation of the damage can provide objective bases for developing strategies to protect habitats. Swine damage to native wet pine-flatwoods at three state parks in Florida was monitored from winter 2002 to winter 2003. Economic valuations of damage were based on the US dollar amounts that wetland regulators have allowed permit applicants to spend in attempts to replace lost resources. The parks had different swine management histories and the damage patterns differed among them over time. Swine were intensively removed in 2000 from the first park, and it initially had the lowest habitat damage at 1.3%, but as a result of natural and artificial population growth this damage rose to 5.4% by the conclusion of the study, and was valued at US$ 19 193–36 498 ha−1. The second park had no history of swine harvest and, over the monitoring period, damage escalated from 2.6%–6.4%, with an associated value of US$ 22 747–43 257 ha−1. Swine were managed as game animals in the third park prior to its inclusion into the state parks system in 2000. Within this park, the proportion of area damaged decreased from 4.3%–1.5%, valued at US$ 5 331–10 138 ha−1. This decrease may be a result of human activities associated with development of the park's infrastructure causing dispersal of animals conditioned to avoid humans by hunting. Damage was highly scattered in each park, as evidenced by a much higher proportion of sampling sites showing damage than the actual proportion of land area damaged. The dispersed nature of small amounts of damage would increase the effort required to recover habitat and thus damage value estimates are probably conservative. It was also impossible to incorporate values for such contingencies as swine impact to state and federally listed endangered plants in the parks, some of which are found nowhere else in the world.